Selectively Breaking Bicontinuous Microphase Confinement for Sustainable and Unprecedented Superlubricating Hydrogels

Conventional lubricating hydrogels struggle to simultaneously achieve excellent mechanical strength and interfacial lubrication due to the bulk and surface homogeneity. To address this, we developed a hydrogel with superior lubrication and load-bearing performance by selectively breaking bicontinuous microphase confinement on the hydrogel surface, in which the hydrogen-bond association within the microphase is dissociated to release the confined polymer chains. The bicontinuous matrix acts as the load-bearing phase, utilizing its percolated hydrophilic/hydrophobic microphase interfaces for dissipation (elastic modulus ∼417 MPa). The broken microphases form a brush-like lubricating layer with strong hydration and entropic repulsion (coefficient of friction ∼0.0029). This structure effectively reduces shear stress and blunts friction cracks to improve wear resistance, and the percolated hydrophilic phase maintains sustainable lubrication via self-regeneration (coefficient of friction ∼0.0034, 50 N load, 100k cycles). This system also exhibits a closed-loop recycling, retaining 98.5% of its friction-reducing capabilities even after 100 cycles of reuse. Among reported lubricating hydrogels, this system achieves the lowest coefficient of friction with the highest modulus. This strategy provides a sustainable, innovative solution for lubrication systems under extreme conditions.